Wind turbine housing and apparatus

ABSTRACT

A wind driven turbine installation has a rotatable enclosure with closable inlet and outlet openings. The rotatable enclosure includes a driving arrangement and a wind direction sensor arrangement that monitor the incident wind direction and align the enclosure such that the inlet opening is aligned with the prevailing wind direction. The inlet opening includes an acceleration passage which increases wind velocity and directs the wind to a wind driven turbine device disposed within the installation. The turbine device includes a converging inlet passage, a secondary inlet passage, and an exhaust passage. A turbine rotor is disposed within the turbine device such that wind entering the primary inlet drives the rotor in part by following rotor vanes, and in part by passing across the rotor vanes. Wind entering the secondary passage is redirected toward the primary inlet and drives the rotor in the forward direction. Wind from the secondary passage is confluent with wind from the primary inlet that passes through the rotor. The confluent air flow exhausts through the rotor at the exhaust opening where that portion of the primary air which follows the rotor is also exhausted. The wind turbine device may be mounted for rotation about a vertical axis within the secondary housing so as to adjust itself to the direction of the prevailing wind.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of copending patentapplication Ser. No. 08/091,432, filed Jul. 15, 1993,now U.S. Pat. No.5,332,354, for "Wind Turbine Apparatus".

BACKGROUND OF THE INVENTION

The present invention relates generally to wind driven turbines. Moreparticularly, the invention concerns a partial admission centrifugalturbine powered by atmospheric wind to drive an electrical generator.

Wind driven generators are known in the art. For example, a wind poweredgenerator using a wind driven rotor having a plurality of parallel vanesarranged circumferentially around a vertical axis has been used to drivea generator. A housing around the rotor has a movable inlet vane todirect wind toward one side of the rotor. The housing itself may berotatable so as to adjust to the direction of oncoming wind. Further, ifdesired, the assembly can be mounted on top of an automobile. See U.S.Pat. No. 5,038,049, issued to Kato on Aug. 6, 1991.

Generators are also known in which air supplied by wind is separatedinto a plurality of parallel portions which are applied to differentparts of the rotor. See U.S. Pat. No. 4,350,900, issued to Baughman onSep. 21, 1982. Moreover, various configurations for wind driven vanesused in wind turbines are known, such as symmetric airfoil shaped vanesof the Baughman patent, straight but radially canted vanes (see U.S.Pat. No. 4,179,007 issued to Howe on Dec. 18, 1979), radially curvedvanes without inlet flow direction (see U.S. Pat. Nos. 4,278,896, issuedto McFarland on Jul. 14, 1981; 4,031,405, issued to Asperger on Jun. 21,1977; and 2,667,589, issued to Levrero on Jan. 26, 1954), radiallycurved vanes with inlet flow direction (see U.S. Pat. Nos. 4,047,834,issued to Magoveny et al. on Sep. 13, 1977; and 1,903,307, issued toGillio on Apr. 4, 1933), Darrieus type rotors (see U.S. Pat. No.4,162,410, issued to Amick on Jul. 24, 1979). It is also known toprovide a variable area throat arrangement for wind driven turbines.See, U.S. Pat. No. 3,944,840, issued to Troll on Mar. 16, 1976.

Other rotor arrangements, such as axial flow configurations, are alsoknown, including for example, U.S. Pat. Nos. 4,508,973, issued to Payneon Apr. 2, 1985, 4,398,096, issued to Faurholtz on Aug. 9, 1983, and4,288,704, issued to Bosard on Sep. 8, 1981.

In general, however, the known prior art devices use turbine blades likewindmills, that is, wind is used to push the blades. Some prior artdevices use the turbine blades such that wind aerodynamically interactswith the blades to drive them. However, the known prior art devices arenot seen to use wind to push the blades in part of a blade channel whileaerodynamically driving the blades at other parts of the channel, whilesubstantially all of the blade cascade is used to drive the turbine withone and/or the other wind-and-blade interaction. Accordingly, the priorart devices do not use the atmospheric power source in the mostadvantageous manner.

SUMMARY OF THE INVENTION

A wind driven turbine which overcomes the problems and disadvantages ofthe prior art devices includes a plurality of turbine blades arrangedcircumferentially in a rotor about an axis of rotation, and parallelwith that axis. The rotor is mounted in a housing which provides aprimary air inlet, a secondary air inlet, an air outlet, and a bafflemeans for directing air flow from the primary and secondary air inletsto the air outlet such that a portion of the ingested air passes throughthe turbine blades once, a second portion of the ingested air passesthrough the turbine blades twice, and the secondary air flow passesthrough the turbine blades twice.

By arranging the secondary air inlet near the air outlet, thearrangement permits the primary air flow to drive turbine bladesreceding from the primary air inlet while the secondary air flow drivesturbine blades advancing toward the primary air inlet. Accordingly, anincreased mechanical advantage on the rotating turbine blades isobtained.

To direct the primary air flow toward the receding turbine blades, theprimary air inlet defines a channel which is asymmetric with respect tothe housing when viewed in a plane perpendicular to the axis ofrotation. With such an arrangement, the primary air flow receivesdirectional bias toward the concave side of the turbine blades as wellas a flow component tangential to the axis of rotation. Accordingly, theprimary air flow splits so that a first part pushes the receding turbineblades through the blade channel of the housing while a second part ofthe flow aerodynamically drives the turbine blades while flowingradially inwardly over them and into a central channel of the housing.That second pan exhausts from the central channel, passing radiallyoutwardly through the turbine blades and into the outlet opening therebyaerodynamically driving the turbine blades a second time. Meanwhile, thefirst part of the primary air flow joins the second pan at the outletopening.

The secondary air flow may be collected axially above and below theturbine rotor and exhausted directly into the rotor channel from aposition near the outlet opening. In this fashion, the secondary airflow is obtained from relatively undisturbed air passing above and belowthe turbine housing. The secondary air drives the turbine bladesforwardly toward the primary air inlet until there is fluidcommunication with the central channel of the turbine housing. Thesecondary air is confluent with the second part of the primary air flow,and in the same manner as the primary air flow, passes in aerodynamicdriving relationship through the turbine blades and exhausts through theoutlet opening.

The turbine housing is mounted for rotatable movement about a verticalaxis parallel to, and preferably coincident with, the rotational axis ofthe turbine rotor. The turbine housing includes means responsive to windpressure to align the primary air inlet with the prevailing winddirection. Accordingly, the wind turbine is self positioned relative tothe wind.

For large installations, such as on the roof of a building, a secondaryhousing may be provided to shroud the entire wind turbine. That housingis preferably rotatable about the same vertical axis as that aroundwhich the wind turbine itself is rotatable. Preferably, the secondaryhousing includes a control system which rotates it to align the axis ofits opening with the prevailing wind direction.

To increase both the mass flow rate and the velocity of wind enteringthe primary inlet of the wind turbine, the secondary housing inletincludes convergent walls. Additionally, the longitudinal axis throughthe convergent inlet is aligned to intersect the axis of rotation forthe wind turbine housing to thereby deliver the wind energy efficientlyto the wind turbine. The convergent walls of the housing inlet define anoutlet that is narrower but higher than the wind turbine primary inlet.Such an arrangement allows some tolerance in the angular alignmentbetween the wind turbine and the inlet axis of the secondary housingthereby accommodating lateral perturbations in the prevailing winddirection. Furthermore, the wind passing above and below the windturbine primary inlet can be collected by the secondary inlet to enhanceoperation of the wind turbine.

BRIEF DESCRIPTION OF THE DRAWINGS

Many objects and advantages of the wind turbine according to the presentinvention will be apparent to those skilled in the art when thisspecification is read in conjunction with the attached drawings whereinlike reference numerals are applied to like elements and wherein:

FIG. 1 is a schematic perspective view of a wind turbine according tothe present invention;

FIG. 2 is a is a schematic perspective view of the wind turbine of FIG.1 with the top removed but the central baffles left in place;

FIG. 3 is a schematic plan view of the wind turbine of FIG. 1;

FIG. 4 is a schematic perspective view of the turbine rotor of the windturbine of FIG. 1;

FIG. 5 is a schematic view of the arrangement of a turbine blade on theturbine rotor;

FIG. 6 is a schematic perspective view of a secondary housing for thewind turbine of FIG. 1;

FIG. 7 is a side elevation of the secondary housing of FIG. 6 showingthe wind turbine inside the inlet opening;

FIG. 8 is a perspective view of the secondary housing of FIG. 6 with thetop removed to show the arrangement of the wind turbine;

FIG. 9 is a side view of the wind turbine in the secondary housing;

FIG. 10 is a top view of the secondary housing arrangement with the roofremoved;

FIG. 11 is a perspective view of a second embodiment of the windturbine;

FIG. 12 is a perspective view of the second embodiment with the uppercowling removed to show the flowpath and the auxiliary air duct;

FIG. 13 is a perspective view of the second embodiment with the uppercowling and auxiliary air duct removed;

FIG. 14 is a side view of the second embodiment of the wind turbine inthe secondary housing;

FIG. 15 is a perspective view of the second embodiment in a secondaryhousing with the roof removed for clarity; and

FIG. 16 is a plan view of the arrangement of FIG. 15.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A wind driven turbine assembly 20 (see FIG. 1) includes a primaryhousing 22 which may be fashioned frown sheet metal, plastic material,fiber reinforced composite material, or any other suitable conventionalengineering material. Since the entire structure of the turbine assembly20 needs to be responsive to wind direction, it is important that allmaterials used in the construction be as light as possible. To this end,sheet material can be used as much as possible to assure that thestructure is light.

The housing 22 preferably includes a primary inlet opening 24, at leastone secondary inlet opening 26, and an exhaust opening 28. These variousopenings communicate with one another through internal flow passages inthe manner to be described.

The primary inlet opening 24 is positioned at one end of the housing 22and includes an entry portion 30 which defines a capture area havingsubstantially constant cross-sectional area. Moreover, the forward edge25 of the primary inlet opening 24 curves outwardly at the center (seeFIG. 3). In addition, the forward edge 25 of the top curves upwardlywhile the forward edge of the bottom curves downwardly (see FIG. 7). Theoutward curvature of the forward edge 25 above the top and below thebottom is effective to increase the capture area for the turbineassembly 20. The outward curvature of the forward edge 25 forwardly ofthe turbine assembly 20 provides an arcuate capture area across thefront of the turbine assembly 20.

As can be seen more clearly in FIG. 2, internal walls 32, 34 of theinlet define a constriction in the cross-sectional flow area within thehousing 22. Moreover, these internal walls 32, 34 are asymmetricalrelative to a longitudinal axis through the turbine assembly 20 andasymmetrical to a vertical plane containing the longitudinal axis andthe axis of rotation. With this arrangement of the internal walls 32,34, wind entering the primary inlet opening 24 receives a lateralvelocity component directed toward a first sidewall 36 of the housing22. That lateral velocity component is, in addition tangentiallydirected to a turbine rotor contained in the housing 22.

The secondary inlet opening 26 (see FIG. 1) is preferably disposed neara second side wall 38 of the housing 22 and closer to the exhaustopening 28 than to the primary inlet opening. The secondary inlet ispreferably defined in part by a cowling 40 secured to the top surface ofthe housing 22. As illustrated, the portion of the cowling 40 mostclosely adjacent to the exhaust opening 28 is preferably hired so thatair flows smoothly over the cowling 40 with minimal turbulence. A pairof symmetrically disposed secondary inlet openings, each with acorresponding cowling 40, is preferred. Such an arrangement collects airfrom above the top surface of the housing and from beneath the bottomsurface of the housing. Symmetry of the secondary inlet openings 26about a horizontal plane passing through the middle of the turbineassembly 20 balances the forces on the housing 22 imposed by collectionof the secondary air flows.

Positioned at the back end of the housing 22 is a guidance means 42 fordirecting the primary inlet opening into general alignment withdirection of ambient wind. The guidance means 42 preferably includes asymmetric pair of directional fins 44, 44' which, respectively, extendabove the top surface and below the bottom surfaces of the housing 22.These directional fins 44, 44' are proportioned to effectively swing thewind turbine assembly 20 about a vertical axis so that the inlet opening24 is properly positioned. Considering that the secondary inlet openings26 are symmetrical to a horizontal plane while being asymmetrical to thevertical axis, the directional fins 44, 44' may be canted or inclinedrelative to the plane of the associated sidewall 36, 38 by apredetermined angle. In such a manner, the directional fins 44, 44' willcompensate for the asymmetry of forces imposed by the secondary inletopenings relative to the vertical axis.

While the fins 44, 44' are illustrated as being generally plate likeappendages, their shape and location are not important. The importantaspect is the efficacy of the guidance means 42 to compensate forunbalanced forces associated with the secondary inlet openings 26 and tokeep the primary inlet opening 24 aligned with the ambient wind.Furthermore, if desired, the guidance means 42 can be controllable sothat it generates different force levels as may be necessary atdifferent wind velocities to properly orient the inlet opening 24 withthe ambient wind direction.

As can best be seen from FIG. 2, a baffle arrangement inside the housing22 for directs airflow between the primary inlet 24, the exhaust oroutlet opening 28, and a secondary airflow plenum chamber 46. Thesecondary airflow plenum chamber 46 is in fluid communication with theback portion of each secondary inlet opening 26 through correspondingopenings 80 (see FIG. 3) in the upper and lower housing surfaces. Thoseopenings 80 are covered by the cowlings 40 (FIG. 1) which cooperate todirect the secondary airflow from the secondary inlet openings 26 to theopenings 80 and then into the plenum chamber 46. The baffle arrangement(FIG. 2) also defines an annular path 50 in which an annular cascade ofturbine vanes 52 is positioned. This annular path 50 provides theprincipal flow path for air between the primary inlet 24 and the outletopening 28. In order to efficiently use the energy from wind, the radialclearance between the blades 52 and the walls of the annular channel 50are selected to be as small as reasonably possible, thereby preventingair leakage over and around the blades 52.

A central part of the baffle arrangement defines the inner surface ofthe annular path 50 and is divided into two portions 54, 56. Theseportions 54, 56 further define a secondary passage or channel 58 betweenthe primary inlet 24 and the outlet 28. Each portion 54, 56 has a firstwall facing, and partially defining, the annular path 50 as well as asecond wall facing, and partially defining, the central secondarychannel 58. Preferably, these portions 54, 56 are attached to the coverof the turbine assembly. In some structural arrangements of the housingitself, a cover plate may extend between the first and second walls atthe top of these portions as well as at the bottom thereof. As can beseen in the attached figures, the two portions 54, 56 are substantiallymirror images of one another, with the exception of the inlet end 55 ofthe first portion 54 (see FIG. 3). The inlet end 55 may be rounded, orfaired, to facilitate the flow of air from the annular path 50 into thecentral Channel 58 defined between the two portions 54, 56. The precisecontour for the inlet end 55 may be varied to accommodate conventionaldesign parameters and flowpath analyses.

Positioned in the outer wall of the annular path 50 between thesecondary airflow plenum chamber 46 and the primary inlet 24 iscontrolled vent passage 60. The vent passage 60 is defined by the bafflearrangement and extends between the annular path 50 and the secondsidewall 38 of the primary housing 22. A suitable conventional valve,such as a flat plate pivotable about a vertical axis, may be installed,for example, at the outlet of the vent passage 60 to regulate airflowtherethrough. Other positions for such a valve arrangement in the ventpassage are also possible and may be preferred for various reasons. Thisvent passage 60 is considered to be an option to the baffle arrangementfor use in application where secondary inlet airflows would interferewith the primary airflow. In such circumstances, the vent passage 60 canbe opened to vent excess secondary airflow to the atmosphere.

The outer wall of the annular path 50 can be relieved radially outwardlyat the end adjacent to the inlet wall 34. Particular proportions of thechamber 61 which is formed in that outer wall can be selected so as toprovide the best aerodynamic behavior for air flowing in the path 50toward the inlet 24 for discharge into the channel 58. Importantcharacteristics of the chamber 61, however, are that it be faired topromote smooth airflow with minimal turbulence. The chamber 61 canfunction to reduce or minimize turbulence between (a) the primaryairflow entering through the primary inlet and (b) the secondary airflowadvancing from the plenum chamber 46.

Each blade 52 in the annular cascade is generally cylindrical in shapein that the generatrix of the walls moves in a closed path in a plane.Moreover, each blade 52 has a concave wall portion 62, and, a convexwall portion 64. The convex wall portion 64 protrudes in the directionof circular movement of the annular cascade 52 about a vertical axis ofrotation. One end of each blade 52 is attached to a rotor 66 (FIG. 4)with a cantilever mounting arrangement, the combination of the blades 52with the rotor 66 being a wind turbine means. The rotor 66 may bedetachably connected to a vertical axle so that the rotor is readilyinterchangeable with other rotors designed for particular operatingconditions.

Since the turbine means is to be driven by naturally occurring wind, itis ordinarily important that the turbine means be as light as possible.Where lightest possible weight is desired, the turbine blades may behollow so as to minimize their weight, see for example the blade 52'where the top end closure has been removed to show the hollowconfiguration. A light weight foam material may, if desired, be disposedinside the blades to enhance their stiffness while maintaining thenecessary low weight attribute.

Other considerations, including operating conditions where the ambientwind has erratic velocity perturbations, may dictate that blade designbe adjusted to other than the lightest possible weight. For example,where the ambient wind is gusty, heavier blades may be desired to getthe advantage of momentum and inertia that would come from a greatermass. Such increased momentum and inertia should dampen fluctuations inturbine wheel rotational rate that otherwise could result from such windspeed variations.

For light weight wind turbine installations, it is further contemplatedthat the rotor assembly will be designed so as to be easily replaceable.In this way, several turbine rotor assemblies can be designed, each fora different wind velocity. By simply removing the cover for the windturbine assembly, the turbine rotor assembly is accessible and can bereadily exchanged for a different turbine assembly adapted for theexpected wind conditions. Thus, such interchangeable turbine rotorassemblies permit the operation to be tailored to the ambient windconditions.

Furthermore, it may be desirable to use replaceable baffles 54, 56 inthe center of the turbine assembly to accommodate different operatingconditions. To this end it is contemplated that a variety of turbineassembly covers may be provided, each having differently shaped contoursfor the replaceable baffles 54, 56. For example, baffles with differentthroat area dimensions may be provided, as well as baffles where thethroat area dimensions are the same but different passage contoursand/or configurations are provided. With this flexibility in design ofthe internal baffles 54, 56 operating conditions for the wind turbinecan be optimized.

While blade design may be optimized further, it is presently envisionedthat each blade 52 is mounted on the rotor 66 (see FIG. 5) such that achord line 68 extending between the radially outer edge of the blade 52and the radially inner edge of the blade 52 makes an angle θ with aradial line 70 passing through the center of rotation 72 and theradially outer edge of the blade. The angle θ is measured as positive inthe circumferential direction opposite to the direction of turbinerotation. Preferably, the angle θ is selected to be greater than zero sothat the radially inner edge of the blade is angularly disposed in anadvanced position relative to the radially outer edge of the blade.

Operation of the wind turbine assembly when exposed to ambient wind canbest be understood from FIG. 3. As the ambient wind, or primary airflow,70 enters the primary inlet opening 24, it accelerates to pass throughthe converging cross-sectional area defined by the first and secondinternal walls 32, 34 in conjunction with the upper and lower surfacesof the flow path. The asymmetric arrangement of these internal walls 32,34 induces a secondary velocity component in the primary airflow, whichcomponent is transverse to the longitudinal axis of the housing 22. Moreparticularly, the secondary velocity component is directed tangentiallyof the turbine rotor 66.

A first portion 72 of the primary airflow 70 enters a primary portion 74the annular path 50 and pushes the turbine blades 52 through thatprimary portion 74--thus driving the rotor. A second portion 76 of theprimary airflow 70 simply passes radially through the annular bladecascade to the central channel 58. As that second portion 76 passesthrough the annular cascade between the inlet opening 24 and the centralchannel 58, it aerodynamically interacts with the blades 52 and impartstangentially directed forces thereon, also causing rotation of theturbine rotor 66 about its axis.

Simultaneously, a secondary airflow 78 collected by the cowling 40(FIG. 1) enters the secondary airflow plenum chamber 46 through theopening 80 (FIG. 3) in the housing. That secondary airflow 78 enters asecondary portion 79 of the annular path 50 extending from the plenumchamber 46 to the primary inlet opening 24 and pushes the blades 52forwardly toward the primary inlet 24. Should the secondary airflow 78be so great that it adversely affects the primary airflow 70, a portion82 of the secondary airflow can be bled off through the vent channel 60and dumped to the atmosphere. The remaining portion of the secondaryairflow 78 moves forwardly into confluence with the second part 76 ofthe primary airflow 70 and enters the central channel 58.

The combined flow of the second part of the primary airflow and thesecondary airflow pass through the central channel 58 where the combinedflow may be accelerated by a cross-sectional area restriction. Whilethat area restriction is symmetrically located relative to the axis ofrotation in FIG. 3, the area restriction can be positioned at thedownstream end of the channel--or at any other desired location. Thisaccelerated combine flow then moves radially outwardly across the blades52 of the annular cascade, aerodynamically driving the turbine means,and exhausting through the outlet opening 28. At the outlet opening 28,the first part 72 of the primary airflow 70 is confluent with the otherpart of the primary airflow and the secondary airflow.

As a consequence of this arrangement of primary and secondary airflows,the turbine means is driven in the rearward direction by part of theprimary airflow and is driven in the forward direction by the secondaryairflow. Moreover, the turbine rotor is driven aerodynamically at boththe inlet and exhaust locations where air enters and leaves the centralchannel 58. Meanwhile, the turbine is driven impulsively by the primaryand secondary airflows in the annular path or channel 50.

The turbine rotor may, for example, be attached to a suitableconventional electric power generator which converts the rotationalenergy imparted to the turbine by the primary and secondary airflowsinto electrical energy.

The wind turbine of this invention may be used in a variety ofenvironments and may be scaled, or sized, as necessary for efficientutilization of wind energy. A small unit could be mounted on a car tosupplement or supply the electrical requirements. Larger units might beused in open areas for supplementation and/or supply of householdelectricity requirements. Even larger units may be used on buildings asa supplement to the electrical power requirements.

One large scale installation suitable for use of a wind turbine mightinvolve mounting the wind turbine on the roof of a building to gainaccess to stronger winds and to minimize air current distortions fromadjacent structures. A roof-top installation envisioned here includes asecondary housing 100 (FIG. 6) having a roof structure 102 supported onat least one generally circular array of columns 104. If necessary tosupport the weight of the roof, a second set of columns 106 (FIG. 8) maybe disposed inside the housing 100. While the sidewall 108 is shown asbeing circular, there may be other configurations that would bepreferred or that may have further advantages. For example, a structurewhich is symmetric about a vertical plane containing the axis ofrotation could have a width which is smaller than its length so that thesidewall itself would have a preferred orientation relative to the windand would exhibit some selforientation tendencies.

The secondary housing 100 also includes a sidewall 108 (FIG. 6) arrangedto hang from the roof structure 102. The sidewall 108 has an inletopening 110 and a discharge opening 112 (FIG. 8). The sidewall 108 issuspended from the roof structure 102 in such a way that the sidewall108 can be rotated about a vertical axis in order to orient the inletopening 110 in the direction of the prevailing wind. While a variety ofarrangements will be apparent to those skilled in the art, a possiblesuspension arrangement might involve a plurality of rollers mounted tothe roof structure for rotation about horizontal axes and supporting, ontop of the rollers, a ring from which the sidewall 108 is suspended. Asuitable conventional motor drive assembly may then be provided todrivingly engage the ring and move the sidewall 108 relative to the roofstructure 102. A suitable conventional wind direction sensing device isemployed to determine the prevailing wind direction. That wind directionsensing device is operatively connected with the motor drive assembly tomove the sidewall 102 so that its inlet opening 110 is properlypositioned.

To accommodate those situations where the wind turbine is to be shutdown, e.g. for repair, or those situations where the prevailing wind hastoo high a velocity, both the inlet opening 110 and the outlet opening112 are provided with a set of control doors. The inlet opening controldoors 114, 116 are mounted to be controllably driven so as to sliderelative to the sidewall 108. Likewise, the exhaust opening controldoors 118, 120 are mounted to be controllably driven so as to sliderelative to the sidewall 108. In this manner, the front control doors114, 116 can be positioned in a continuous range of positions betweenfully exposing the inlet opening 110, partially covering the inletopening 110, and fully closing the inlet opening 110. The rear controldoors 118, 120 can be positioned with the same range of functionalpositions as the from control doors 114, 116.

So as to direct ambient wind and accelerate that wind to the turbineassembly 20, the inlet opening 110 is further defined by curved walls(FIG. 7). The inlet sidewalls 122, 124 are symmetrical to a verticalplane passing through the center of the inlet opening 110 and thevertical axis of the housing 100. Similarly, the inlet top wall 128 andthe inlet bottom wall 126 are symmetrically disposed relative to ahorizontal plane passing through the center of the inlet opening 110.These symmetrical pairs of inlet walls define a restricted area opening130 having a width that is slightly smaller than the width of the windturbine assembly 20 and having a height which is larger than thevertical height of the wind turbine assembly 20. With this arrangement,the inlet opening 110 supplies a uniform velocity air stream acrosssubstantially the entire width of the wind turbine assembly 20 whilethat same air stream velocity is provided to the secondary inletopenings 26 of the wind turbine assembly 20.

The wind turbine assembly 20 is itself mounted for rotation about avertical axis on a pylon 132 (FIG. 8). Considering that the turbineassembly 20 should be self-adjusting to the wind direction throughaction of the guidance means 42, the assembly 20 is preferably mountedto the pylon 132 by a large diameter, low friction bearing, such as aball bearing. When the turbine assembly is a large scale installation,it may also be desired to provide a motor drive to augment, or evencompletely replace, the aligning action of the guidance means 42.

Where a second set of roof support columns 106 is used, the wind turbineassembly 20 is positioned so that it can freely rotate within thesecondary roof support columns 106 at a substantially constant radialdistance therefrom. Moreover, the inlet opening 110 and associatedsidewalls are designed to extend toward the turbine assembly 20 so as toprovide the closest reasonable radial proximity between the dischargeopening 130 and the wind turbine inlet (FIG. 9). Where the second roofsupport columns 106 are used, that closest reasonably proximity will besufficient to provide radial clearance between the inlet openingstructure and the columns 106 as well as radial clearance between thewind turbine assembly 20 and the columns 106.

In an installation such as that shown, an electrical generator can beplaced within the support pylon 132. In that way the generator is inclose proximity to the turbine means as well as being in a protectedhousing.

During operation of the installation (FIG. 10), the sidewall assembly108 is driven so that the axis of symmetry for the inlet opening 110 andits structure is in general alignment with the prevailing winddirection. As the wind 140 blows it enters the inlet opening 110 and isaccelerated by the convergent area passage of the inlet openingsidewalls. A major portion of the accelerated flow 142 enters theprimary inlet of the wind turbine assembly 20. Another portion 144 ofthe accelerated flow 142 which bypasses the inlet opening 24 enters thesecondary inlet openings 26 of the wind turbine assembly 20. Ultimately,the air streams that pass through the turbine assembly 20 are exhaustedtherefrom and pass out of the secondary housing 100 through thedischarge opening 112.

That part of the accelerated flow 142 which does not pass through theturbine assembly 20 is available to interact with the positioning orguidance means 42 of the turbine assembly 20 so as to move the primaryinlet 24 into general alignment with the inlet opening 110--that is, thelongitudinal axis of the turbine assembly 20 is in general alignmentwith the longitudinal axis through the inlet opening 110.

Perturbations in the direction of prevailing wind are readilyaccommodated by this installation. For example, by sizing the dischargeopening 130 of the inlet 110 so that it is narrower than the primaryturbine inlet opening, predetermined angular perturbations of winddirection will not affect the mass flow of air entering the turbineassembly 20. Moreover, by mounting the wind turbine assembly 20 forrotation independently of the sidewall structure 108, the wind turbineassembly 20 can react more quickly to wind direction perturbations byvirtue of its lower inertia.

Turning now to FIG. 11, a second embodiment of the wind turbine of thisinvention is depicted. The following discussion of the second embodimentwill concern features that are different from the firstembodiment--features that are common to both embodiments will not berepeated in the interest of brevity. It will be understood that wherethe same reference numeral is used in both the first and secondembodiments the feature associated with that reference numeral is thesame.

The principal differences between the first embodiment and the secondembodiment are evident from a comparison of FIG. 1 with FIGS. 11 and 12.Specifically, the primary housing (viewed from above) is faired from theinlet end to the outlet end with the center portion being laterallyenlarged to accommodate the turbine wheel. In addition, the cowlings 40over the secondary inlet openings of the first embodiment (FIG. 1) havebeen replaced by internal ducts (FIG. 12) which do not protrude abovethe faired top and bottom. The top of the second embodiment, rather thanbeing substantially planar as in FIG. 1, is faired from front to backand from side to side so as to provide smoother, less turbulent, airflow above and below the housing. The bottom of the second embodiment isa mirror image of the top.

The primary housing 222 (FIG. 11) may be fashioned from sheet metal,plastic material, fiber reinforced composite material, or any othersuitable conventional engineering material. Since the entire structureof the turbine assembly 20' needs to be responsive to wind direction, itis important that all materials used in the construction be as light aspossible. To this end, sheet material can be used as much as possible toassure that the structure is light.

The housing 222 preferably includes a primary inlet opening 224, atleast one secondary inlet opening 226 (FIG. 12), and an exhaust opening228. These various openings communicate with one another throughinternal flow passages in the manner described above in connection withthe first embodiment.

The primary inlet opening 224 is positioned at one end of the housing222 and defines a capture area. The forward edge 225 of the primaryinlet opening 224 curves outwardly at the center (see FIG. 12). Inaddition, the forward edge 225 of the top curves upwardly while theforward edge of the bottom curves downwardly (see FIG. 11). The outwardcurvature of the forward edge 225 above the top and below the bottom iseffective to increase the capture area for the turbine assembly 20'. Theoutward curvature of the forward edge 225 forwardly of the turbineassembly 20' provides an arcuate capture area across the front of theturbine assembly 20'.

As can be seen more clearly in FIG. 12, internal walls 232, 234 of theinlet define a constriction in the cross-sectional flow area within thehousing 222. Moreover, these internal walls 232, 234 are asymmetricalrelative to a longitudinal axis through the turbine assembly 20' andasymmetrical to a vertical plane containing the longitudinal axis andthe axis of rotation. With this arrangement of the internal walls 232,234, wind entering the primary inlet opening 224 receives a lateralvelocity component directed toward a first sidewall 236 of the housing222. That lateral velocity component is, in addition tangentiallydirected to a turbine rotor contained in the housing 222. The secondembodiment does not have a substantially constant area portion at theinlet 224, accordingly, the contour of the walls 232, 234 at the forwardend of the turbine assembly 20' is different than the walls 32, 34 ofthe first embodiment.

The secondary inlet opening 226 (see FIG. 12) is preferably disposednear the entrance to the turbine itself, much closer to the primaryinlet opening 224 than to the exhaust opening 228. The secondary inlet226 is preferably defined in part by an internal duct 240 secured to thetop surface of a planar cover (not shown in the interest of clarity)over the flow path within the turbine assembly 20'. Similarly, a planartop surface covers the bottom of the flow path. As illustrated, theinternal duct 240 converges from the inlet to its outlet so that airflows smoothly therethrough to the aft plenum chamber 46. While only oneduct 240 can be seen in FIG. 12, a second duct, symmetrically positionedbelow the flow path may also be provided, as desired. Such anarrangement collects air from the housing inlet. Symmetry of thesecondary inlet openings 226 about a horizontal plane passing throughthe middle of the turbine assembly 20 balances the forces on the housingimposed by collection of the secondary air flows.

The secondary airflow plenum chamber 46 is in fluid communication withthe back portion of each secondary inlet opening 26 through thecorresponding ducts 240 and the corresponding openings 80 (not shown) inthe upper and lower planar surfaces. Those openings 80 are covered bythe back portion of the ducts 240 (FIG. 12) which cooperate to directthe secondary airflow from the secondary inlet openings 226 to theopenings 80 and then into the plenum chamber 46.

Operation of the second embodiment of the wind turbine assembly 20' whenexposed to ambient wind is essentially the same as that of the firstembodiment. As the ambient wind, or primary airflow, 70 (see FIG. 13)enters the primary inlet opening 224, it accelerates to pass through theconverging cross-sectional area defined by the first and second internalwalls 232, 234 in conjunction with the convergent upper and lowersurfaces of the flow path inlet. The asymmetric arrangement of theseinternal walls 232, 234 induces a secondary velocity component in theprimary airflow, which component is transverse to the longitudinal axisof the housing. More particularly, the secondary velocity component isdirected tangentially of the turbine rotor 66.

A first portion 72 of the primary airflow 70 enters a primary portion 74the annular path 50 and pushes the turbine blades 52 through thatprimary portion thus driving the rotor. A second portion 76 of theprimary airflow 70 simply passes radially through the annular bladecascade to the central channel 58. As that second portion 76 passesthrough the annular cascade between the inlet opening 24 and the centralchannel 58, it aerodynamically interacts with the blades 52 and impartstangentially directed forces thereon, also causing rotation of theturbine rotor 66 about its axis.

Simultaneously, a secondary airflow 278 collected by the duct 240 (FIG.12) enters the secondary airflow plenum chamber 46 through the opening80. That secondary airflow 278 enters a secondary portion 79 of theannular path 50 extending from the plenum chamber 46 to the primaryinlet opening 224 and pushes the blades 52 forwardly toward the primaryinlet 224. Should the secondary airflow 278 be so great that itadversely affects the primary airflow 70, a portion 82 of the secondaryairflow can be bled off through the vent channel 60 and dumped to theatmosphere. The remaining portion of the secondary airflow 278 movesforwardly into confluence with the second part 76 of the primary airflow70 and enters the central channel 58.

The combined flow of the second part of the primary airflow and thesecondary airflow passes through the central channel 58 where thecombined flow may be accelerated by a cross-sectional area restriction.While that area restriction is symmetrically located relative to theaxis of rotation in FIG. 13, the area restriction can be positioned atthe downstream end of the channel, or at any other desired location.This accelerated combined flow then moves radially outwardly across theblades 52 of the annular cascade, aerodynamically driving the turbinemeans, and exhausting through the outlet opening 228. At the outletopening 228, the first part 72 of the primary airflow 70 is confluentwith the other part of the primary airflow and the secondary airflow.

As a consequence of this arrangement of primary and secondary airflows,the turbine means is driven in the rearward direction by part of theprimary airflow and is driven in the forward direction by the secondaryairflow. Moreover, the turbine rotor is driven aerodynamically at boththe inlet and exhaust locations where air enters and leaves the centralchannel 58. Meanwhile, the turbine is driven impulsively by the primaryand secondary airflows in the annular path or channel 50.

Like the first embodiment, the second embodiment of the wind turbine maybe used in a variety of environments and may be scaled, or sized, asnecessary for efficient utilization of wind energy.

Moreover, the second embodiment can also be used in a large scaleinstallation such as described above in conjunction with FIGS. 6-10. Insuch an installation, the turbine assembly 20' (FIG. 14) is substitutedfor the turbine assembly 20 (FIG. 9). The turbine assembly 20' (FIG. 15)is generally aligned with the opening 110 of the secondary housing.Furthermore, the turbine assembly 20' is positioned in the secondaryhousing (FIG. 16) so that it can freely rotate about a vertical axiswhile remaining in close proximity to the discharge end of the secondaryhousing inlet 110.

Perturbations in the direction of prevailing wind are readilyaccommodated by this installation. For example, by sizing the dischargeopening 130 of the inlet 110 so that it is narrower than the primaryturbine inlet opening, predetermined angular perturbations of winddirection will not affect the mass flow of air entering the turbineassembly 20'. Moreover, by mounting the wind turbine assembly 20' forrotation independently of the sidewall structure 108, the wind turbineassembly 20' can react more quickly to wind direction perturbations byvirtue of its lower inertia. Further, since the secondary inlets forthis embodiment are disposed within the inlet opening, the maximumvertical spacing between the top and bottom surfaces at the inletopening can be as large as the vertical opening at the back of the inletstructure of the secondary housing. Preferably, however, the maximumvertical spacing is somewhat less than vertical opening.

From the foregoing it will now be apparent that a novel wind turbineassembly and a novel wind turbine installation have been disclosed whichovercome problems of the type faced by the prior art. Moreover, it willbe apparent to those skilled in the art that numerous variations,modifications, substitutions, and equivalents exist for features of theinvention which do not materially depart from the spirit and scope ofthe invention. Accordingly, it is expressly intended that all suchvariations, modifications, substitutions, and equivalents which fallwithin the spirit and scope of the invention as defined in the appendedclaims be embraced thereby.

What is claimed is:
 1. A wind driven turbine device comprising:a housinghaving longitudinally hired sides, a primary inlet opening, a secondaryinlet opening within the primary inlet opening, an outlet opening, andguidance means for orienting the primary inlet opening in generalalignment with atmospheric wind; turbine means for generating rotarypower from atmospheric wind, rotatably mounted in the housing formovement in response to atmospheric wind movements; baffle means fordirecting wind through the housing and the turbine means, the bafflemeans connecting the primary inlet opening, secondary inlet opening, andthe outlet opening of the housing while defining an annular path for theturbine means, directing a first portion of wind from the primary inletthrough a first portion of the annular path, directing wind from thesecondary inlet through a second portion of the annular path and intoconfluence with a second portion of wind from the primary inlet, anddirecting confluent second portion of wind from the primary inlet andwind from the secondary inlet outwardly through the turbine means to theoutlet; and mounting means attached to the housing for rotatablysupporting the housing while permitting movement of the housing about anaxis.
 2. The wind driven turbine of claim 1 wherein the turbine meansincludes a plurality of vanes each having a concave side and a convexside, each vane being mounted in an annular cascade such that wind fromthe primary inlet opening can flow radially inwardly across the turbinemeans.
 3. The wind driven turbine of claim 1 wherein the inlet openingof the housing defines a region of converging cross-sectional area toincrease the velocity of wind approaching the turbine means.
 4. The winddriven turbine of claim 1 wherein the housing includes a pair ofsymmetrically disposed secondary openings and a corresponding pair ofinlet scoops in fluid communication with the respective secondaryopenings and arranged to capture atmospheric wind bypassing the primaryinlet opening.
 5. The wind driven turbine of claim 1 wherein the bafflemeans directs wind from the primary inlet opening so as to induce avelocity component tangential to the turbine means.
 6. The wind driventurbine of claim 1 wherein the turbine means is connected to a generatormeans for generation of electricity in response to rotary movement ofthe turbine means.
 7. The wind driven turbine of claim 1 furtherincluding a secondary housing surrounding the housing and including aconvergent inlet and an outlet, the convergent inlet being in generalalignment with the primary inlet opening and the outlet being in generalalignment with the outlet opening.
 8. The wind driven turbine of claim 7wherein secondary housing is mounted for rotation about a vertical axisand includes sensing means for detecting the atmospheric wind direction,and drive means responsive to the sensing means and connected to thesecondary housing to move the convergent inlet into general alignmentwith the detected wind direction.
 9. The wind driven turbine of claim 7wherein closures are provided for the inlet opening, the closures beingmovable between an open position where the inlet opening is unobstructedand a closed position where the inlet opening is closed to atmosphericwind so that wind flow into the turbine can be controlled.
 10. The winddriven turbine of claim 7 wherein closures are provided for the outletopening, the closures being movable between an open position where theoutlet opening is unobstructed and a closed position where the outletopening has no fluid communication with the atmosphere.
 11. The winddriven turbine of claim 7 wherein the convergent inlet has a dischargewith a width less than the width of the primary inlet opening and aheight greater than the height of the primary inlet opening so that airbypassing the primary inlet can reach the secondary inlet openings.